<?php //$Id: block_online_users.php,v 1.54.2.6 2009/01/09 00:54:05 jerome Exp $

/**
 * This block needs to be reworked.
 * The new roles system does away with the concepts of rigid student and
 * teacher roles.
 */
class block_online_users extends block_base {
	function init() {
		$this->title = get_string('blockname','block_online_users');
		$this->version = 2007101510;
	}

	function has_config() {return true;}

	function get_content() {
		global $USER, $CFG, $COURSE;

		if ($this->content !== NULL) {
			return $this->content;
		}

		$this->content = new stdClass;
		$this->content->text = '';
		$this->content->footer = '';

		if (empty($this->instance)) {
			return $this->content;
		}

		$timetoshowusers = 300; //Seconds default
		if (isset($CFG->block_online_users_timetosee)) {
			$timetoshowusers = $CFG->block_online_users_timetosee * 60;
		}
		$timefrom = 100 * floor((time()-$timetoshowusers) / 100); // Round to nearest 100 seconds for better query cache

		// Get context so we can check capabilities.
		$context = get_context_instance(CONTEXT_COURSE, $COURSE->id);

		if (empty($this->instance->pinned)) {
			$blockcontext = get_context_instance(CONTEXT_BLOCK, $this->instance->id);
		} else {
			$blockcontext = get_context_instance(CONTEXT_SYSTEM); // pinned blocks do not have own context
		}

		//Calculate if we are in separate groups
		$isseparategroups = ($COURSE->groupmode == SEPARATEGROUPS
							 && $COURSE->groupmodeforce
							 && !has_capability('moodle/site:accessallgroups', $context));

		//Get the user current group
		$currentgroup = $isseparategroups ? groups_get_course_group($COURSE) : NULL;

		$groupmembers = "";
		$groupselect = "";
		$rafrom  = "";
		$rawhere = "";

		//Add this to the SQL to show only group users
		if ($currentgroup !== NULL) {
			$groupmembers = ",  {$CFG->prefix}groups_members gm ";
			$groupselect = " AND u.id = gm.userid AND gm.groupid = '$currentgroup'";
		}

		if ($COURSE->id == SITEID) {  // Site-level
			$select = "SELECT u.id, u.username, u.firstname, u.lastname, u.picture, max(u.lastaccess) as lastaccess ";
			$from = "FROM {$CFG->prefix}user u
						  $groupmembers ";
			$where = "WHERE u.lastaccess > $timefrom
					  $groupselect ";
			$order = "ORDER BY lastaccess DESC ";

		} else { // Course-level
			if (!has_capability('moodle/role:viewhiddenassigns', $context)) {
				$pcontext = get_related_contexts_string($context);
				$rafrom  = ", {$CFG->prefix}role_assignments ra";
				$rawhere = " AND ra.userid = u.id AND ra.contextid $pcontext AND ra.hidden = 0";
			}

			$courseselect = "AND ul.courseid = '".$COURSE->id."'";
			$select = "SELECT u.id, u.username, u.firstname, u.lastname, u.picture, max(ul.timeaccess) as lastaccess ";
			$from = "FROM {$CFG->prefix}user_lastaccess ul,
						  {$CFG->prefix}user u
						  $groupmembers $rafrom ";
			$where =  "WHERE ul.timeaccess > $timefrom
					   AND u.id = ul.userid
					   AND ul.courseid = $COURSE->id
					   $groupselect $rawhere ";
			$order = "ORDER BY lastaccess DESC ";
		}

		$groupby = "GROUP BY u.id, u.username, u.firstname, u.lastname, u.picture ";

		//Calculate minutes
		$minutes  = floor($timetoshowusers/60);

		// Verify if we can see the list of users, if not just print number of users
		if (!has_capability('block/online_users:viewlist', $blockcontext)) {
			if (!$usercount = count_records_sql("SELECT COUNT(DISTINCT(u.id)) $from $where")) {
				$usercount = get_string("none");
			}
			$this->content->text = "<div class=\"info\">".get_string("periodnminutes","block_online_users",$minutes).": $usercount</div>";
			return $this->content;
		}

		$SQL = $select . $from . $where . $groupby . $order;

		if ($users = get_records_sql($SQL, 0, 50)) {   // We'll just take the most recent 50 maximum
			foreach ($users as $user) {
				$users[$user->id]->fullname = fullname($user);
			}
		} else {
			$users = array();
		}

		if (count($users) < 50) {
			$usercount = "";
		} else {
			$usercount = count_records_sql("SELECT COUNT(u.id), u.id $from $where GROUP BY u.id");
			$usercount = ": $usercount";
		}

		$this->content->text = "<div class=\"info\">(".get_string("periodnminutes","block_online_users",$minutes)."$usercount)</div>";

		//Now, we have in users, the list of users to show
		//Because they are online
		if (!empty($users)) {
			//Accessibility: Don't want 'Alt' text for the user picture; DO want it for the envelope/message link (existing lang string).
			//Accessibility: Converted <div> to <ul>, inherit existing classes & styles.
			$this->content->text .= "<ul class='list'>\n";
			if (!empty($USER->id) && has_capability('moodle/site:sendmessage', $context)
						   && !empty($CFG->messaging) && !isguest()) {
				$canshowicon = true;
			} else {
				$canshowicon = false;
			}
			foreach ($users as $user) {
				$this->content->text .= '<li class="listentry">';
				$timeago = format_time(time() - $user->lastaccess); //bruno to calculate correctly on frontpage
				if ($user->username == 'guest') {
					$this->content->text .= '<div class="user">'.print_user_picture($user->id, $COURSE->id, $user->picture, 16, true, false, '', false);
					$this->content->text .= get_string('guestuser').'</div>';

				} else {
					$this->content->text .= '<div class="user"><a href="'.$CFG->wwwroot.'/user/view.php?id='.$user->id.'&amp;course='.$COURSE->id.'" title="'.$timeago.'">';
					$this->content->text .= print_user_picture($user->id, $COURSE->id, $user->picture, 16, true, false, '', false);
					$this->content->text .= $user->fullname.'</a></div>';
				}
				if ($canshowicon and ($USER->id != $user->id) and  $user->username != 'guest') {  // Only when logged in and messaging active etc
					$this->content->text .= '<div class="message"><a title="'.get_string('messageselectadd').'" href="'.$CFG->wwwroot.'/message/discussion.php?id='.$user->id.'" onclick="this.target=\'message_'.$user->id.'\';return openpopup(\'/message/discussion.php?id='.$user->id.'\', \'message_'.$user->id.'\', \'menubar=0,location=0,scrollbars,status,resizable,width=400,height=500\', 0);">'
						.'<img class="iconsmall" src="'.$CFG->pixpath.'/t/message.gif" alt="'. get_string('messageselectadd') .'" /></a></div>';
				}
				$this->content->text .= "</li>\n";
			}
			$this->content->text .= '</ul><div class="clearer"><!-- --></div>';
		} else {
			$this->content->text .= "<div class=\"info\">".get_string("none")."</div>";
		}

		return $this->content;
	}
}

?>
